Dynamics and hysteresis in square lattice artificial spin-ice

TL;DR

This paper investigates the dynamic behavior and hysteresis phenomena in a two-dimensional square lattice artificial spin ice model with Heisenberg-like dipoles, revealing phase transitions and magnetic response characteristics.

Contribution

It introduces a real dynamics model for square lattice artificial spin ice with Heisenberg-like spins, extending beyond Ising models, and analyzes thermodynamic and hysteresis properties.

Findings

Specific heat peaks indicate melting-like phase transitions.

Hysteresis loops depend on system parameters and equilibrium conditions.

The model captures dynamic effects beyond static Ising descriptions.

Abstract

Dynamical effects under geometrical frustration are considered in a model for artificial spin ice on a square lattice in two dimensions. Each island of the spin ice has a three-component Heisenberg-like dipole moment subject to shape anisotropies that influence its direction. The model has real dynamics, including rotation of the magnetic degrees of freedom, going beyond the Ising-type models of spin ice. The dynamics is studied using a Langevin equation solved via a second order Heun algorithm. Thermodynamic properties such as the specific heat are presented for different couplings. A peak in specific heat is related to a type of melting-like phase transition present in the model. Hysteresis in an applied magnetic field is calculated for model parameters where the system is able to reach thermodynamic equilibrium.